Frag tank and refugium set up

[Fourthwind]

I have started a small 20 gallon frag tank project. The tank is 18.5"L x 21.5"W x 11.5"T Tomorrow I am picking up a sump / refugium that I got a smoking deal on from ADHI. 24"L x 12"W x16"H (basically a 15 gallon) My question is since I really don't want anything other than racks and corals in the tank, what is best for the refugium for supporting healthy aerobic and anaerobic bacteria levels? Seen so many different options, but almost all that were being talked about were meant for reefs that had live rock already in the tank. I have no doubts I am over thinking this, so I would like the keepers of the almighty frag to sink their two bits into my plans Marine pure, DSB , Fiji Mud, Live rock, combos? How would you set this up?

 

[SynDen]

If this is going on a frag tank, I would say that you should just pack it full of live rock.

 

[Fourthwind]

picked up the refugium today.. Really nice looking unit. Has a lot more room than I thought. Enough to fit sand in the refugium with some live rock, and some marine pure in the pump section. Any tips or tricks I should know setting this all up?